Various prior art devices have been devised for bringing containers which are in a bulk or multiple row arrangement into single row alignment. However, these have inherently had certain disadvantages. Devices have been provided wherein multiple rows of containers are moved downstream on a conveyor belt and diagonal deflectors extend inwardly from both sides to funnel the containers into single file arrangement at the downstream end. Such a device is illustrated in U.S. Pat. No. 1,990,549 to Kimball. These devices have an inherent disadvantage in that the containers tend to bridge across the space between the deflectors and can create a jam resulting in the discontinuance of the flow of containers. Also, such conveyors will only operate satisfactorily at relatively slow speeds, such as under 500 containers per minute.
Roller type conveyors have been provided for conveying multiple rows of containers which are brought into single file by a deflector which extends downstream and diagonally across the conveyor to one side thereof to ultimately bring the containers into single file alignment. Again, such devices must be operated at relatively low speeds. Examples of such devices are shown in U.S. Pat. No. 2,468,290 to Carter and U.S. Pat. No. 2,690,251 to Carter.
A vacuum belt device is illustrated in U.S. Pat. No. 3,352,404 to bring bottles which are dropped down onto the conveyor into longitudinal alignment. This device, however, is not used for bringing multiple rows of containers into single file.
U.S. Pat. No. 4,146,467 to Sauer, et al. discloses a vacuum conveyor for separating misaligned or damaged containers, but has no utility in bringing multiple rows of containers into single file.
A high speed vertical single filer is shown in applicant's U.S. Pat. No. 4,561,806. This device is very efficient and effective for bringing multiple rows of containers into single file at high speed such as in excess of 2,000 containers per minute. Opposite side walls converge and acceleration jets are provided which coact to bring containers into single file alignment as they move from the upstream end to the downstream end. However, one disadvantage is that a relatively long longitudinal path is required in order to accomplish the single filing. Because of the physical constraints presented in some plants, there is not sufficient distance between adjacent stations so that containers can be brought into single file utilizing this vertical single filer. Furthermore, it cannot be used with containers having high frictional surfaces, such as bright containers. Otherwise, jamming will occur at the point of the equilateral triangle formed by the converging containers because of opposite container rotation.
A vacuum single filer is shown in my above-identified U.S. patent application Ser. No. 700,748, filed Feb. 12, 1985. This single filer includes means for arranging a mass of articles into discrete rows of three articles each across a deadplate of the single filer with the articles at the outside end of each row longitudinally aligned with a single file downstream location. The articles are moved at a first predetermined rate of speed. An endless belt vacuum conveyor is provided for moving the discrete rows of articles from the upstream location toward the downstream location at a second and faster rate of speed. The vacuum conveyor extends under the downstream end of the deadplate. The deadplate has a series of longitudinal slots at its downstream edge through which vacuum is drawn by the vacuum conveyor to hold the downstream row in alignment prior to movement onto the belt of the vacuum conveyor. The longitudinal slots prevent the articles from being drafted in an irregular pattern from the downstream edge of the deadplate by air moving downstream across the edge of the deadplate which air is being drawn through slots in the belt. The vacuum holds the outside article in fixed lateral position as it is moved from the upstream location to the downstream location while a diagonal deflector moves the articles in each interior row into single file alignment behind the outside article as the articles are moved from the upstream location to the downstream location. At very high speeds, a difficulty may be encountered in aligning the discrete rows into single file if the outside article in a diagonal row should be held back for any reason. This can occur by the articles rolling against each other and due to the flexibility of the side walls they can be compressed and squeezed together, allowing an interior article to move ahead of an outside article in the same row. If such an event should occur, the inside articles in the row may be positioned far enough ahead of the outside article so that when the articles are being brought into single file alignment an inside article will push the outside article out of position so that it is deflected off of the vacuum belt. This condition can occasionally occur if the containers are not handled in a very precise manner prior to being discharged from the deadplate onto the vacuum belt.